When using resteasy-netty4, it seems that automatic HEAD handling as specified by JAXRS is faulty.

We use a GET /healthcheck endpoint to monitor our services. When our monitoring tool (monit) switched to using HEAD by default when sending requests, we started to notice strange behavior from our APIs. Random errors and what seemed to be corrupted responses.

When we looked into it, we found out that the response body of the /healthcheck was prepended to the response of faulty responses. So we thought it might have been related to resteasy somehow.

It seems that when issue 1365 was fixed, it introduced this behavior. I think, but Im not sure at all, that it may be the NettyResponse buffer that is not properly cleaned and may leak into a subsequent response.